MQTT Test Steps Gone From My ReadyAPI Installation

I am no longer seeing the MQTT test steps available in my ReadyAPI.  I was using them in tests in version 3.7 and tried to upgrade to 3.10, and when I went back to 3.7, they were no longer there. 

I see this message when I open a project that had those test steps:

At least one test step was not added to the test case. Please make sure you have all the plugins installed and reload the project. Skipped test step(s): Publish using MQTT.

I do see the mqtt jars in my directory:C:\Users\nnr6cbq\.soapui\plugins

A fresh install of the application did not solve the issue. I uninstalled 3.10 too so I just have one installation of ReadyAPI on my PC.